An example of a walk-in apparatus for a vehicle seat is disclosed in Japanese Patent laid-open publication No. 8-20266.
The vehicle seat is slidably supported on the vehicle floor through a rail mechanism. The rail mechanism has a pair of lower rails which is secured on the vehicle floor and a pair of upper rails which is slidably supported on the lower rails. The vehicle seat has a seat cushion which is secured to the upper rails of the rail mechanism and a seat back which is rotatably supported on the upper rails of the rail mechanism.
The walk-in apparatus includes a pair of locking plates, a pair of reclining plates, a pair of lever members and a pair of memory plates. The locking plates are arranged on the opposite sides of the vehicle seat. The locking plates are rotatably supported on the upper rails which are secured to the vehicle seat and engage and disengage with the lower rails which are secured on the vehicle floor so as to restrict and achieve the sliding movement of a vehicle seat. The reclining plates are arranged on opposite sides of the vehicle seat and rotated by the forward rotating movement of the seat back. The lever members are arranged on opposite sides of the vehicle seat and connected to the locking plates and the reclining plates. The memory plates are arranged on the opposite side of the vehicle seat and engage and disengage with the lever members.
When the reclining plates rotate by the forward rotating movement of the seat back, the locking plates are moved through the lever members so as to be disengaged from the lower rails of the rail mechanism. Therefore, the sliding movement of the vehicle seat is achieved. As a result, the vehicle seat slides forwardly and provides an adequate opening. When the locking plates disengage, the memory plates are engaged with the lever members, therefore, the locking plates are disengaged from the lower rails until the vehicle seat is returned to an original position before the seat slides forward.
However, the walk-in apparatus needs a pair of memory plates which are arranged on the opposite sides of the vehicle seat. The locking plates may not operate synchronously if the two memory plates do not engage with the lever members at the same time or if the locking plates do not disengage from the lower rails at the same time.